<abstract xmlns="http://www.w3.org/1999/xhtml"><p>In geodetic measurements of deformations in shell cooling towers, an important factor is to optimize the number of points representing the exterior surface of the shell. The conducted analyses of damage to such structures proved that cooling towers exhibited shell deformation consisting of irregular vertical waves (three concavities and two convexities), as well as seven horizontal waves. On this basis, it is claimed that, in accordance with the Shannon theorem, the correct representation of the generated waves requires the measurement of the cooling tower shell in a minimum of 12 vertical and 14 horizontal sections. Such density of the points may not be sufficient to represent local imperfections of the shell. The article presents the results of test measurements and their analysis, which were conducted to verify the assumptions as to the optimal number of measurement points for the shell of a cooling tower. The evaluation was based on a comparative analysis of the data obtained by the Terrestrial Laser Scanning (TLS) method, creating a very detailed model of geometric imperfections in an actual cooling tower with a height of 100 m. Based on the data obtained by the TLS method, point grids of various density were generated. An additional measurement of the cooling tower shell deformation was performed using a precise electronic total station with reflectorless measurement option. Therefore, it was possible to assess the accuracy of measurements by laser scanning in relation to measurements obtained by reflectorless total stations.</p></abstract>

In geodetic measurements of deformations in shell cooling towers, an important factor is to optimize the number of points representing the exterior surface of the shell. The conducted analyses of damage to such structures proved that cooling towers exhibited shell deformation consisting of irregular vertical waves (three concavities and two convexities), as well as seven horizontal waves. On this basis, it is claimed that, in accordance with the Shannon theorem, the correct representation of the generated waves requires the measurement of the cooling tower shell in a minimum of 12 vertical and 14 horizontal sections. Such density of the points may not be sufficient to represent local imperfections of the shell. The article presents the results of test measurements and their analysis, which were conducted to verify the assumptions as to the optimal number of measurement points for the shell of a cooling tower. The evaluation was based on a comparative analysis of the data obtained by the Terrestrial Laser Scanning (TLS) method, creating a very detailed model of geometric imperfections in an actual cooling tower with a height of 100 m. Based on the data obtained by the TLS method, point grids of various density were generated. An additional measurement of the cooling tower shell deformation was performed using a precise electronic total station with reflectorless measurement option. Therefore, it was possible to assess the accuracy of measurements by laser scanning in relation to measurements obtained by reflectorless total stations.

Measurement point density and measurement methods in determining the geometric imperfections of shell surfaces

Department of Engineering Surveying and Civil Engineering, Faculty of Mining Surveying and Environmental Engineering

Faculty of Physics and Applied Computer Science

Reports on Geodesy and Geoinformatics

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

In geodetic measurements of deformations in shell cooling towers, an important factor is to optimize the number of points representing the exterior surface of...

Measurement point density and measurement methods in determining the geometric imperfections of shell surfaces

Published Online: Jul 17, 2018

Page range: 19 - 28

Received: Oct 13, 2017

Accepted: Jan 30, 2018

DOI: https://doi.org/10.2478/rgg-2018-0003

Keywords
cooling towers, geometrical imperfection, minimal point density, deformation

© 2018 Rafał Kocierz et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Measurement point density and measurement methods in determining the geometric imperfections of shell surfaces

Published Online: Jul 17, 2018

Page range: 19 - 28

Received: Oct 13, 2017

Accepted: Jan 30, 2018

DOI: https://doi.org/10.2478/rgg-2018-0003

Keywordscooling towers, geometrical imperfection, minimal point density, deformation

© 2018 Rafał Kocierz et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Keywords
cooling towers, geometrical imperfection, minimal point density, deformation